This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Arthritis is the leading cause of disability in the United States in persons eighteen years and older. Disability arising from arthritic conditions accounts for tremendous health care costs for individuals, their families, employers, and the country. In fact, the Center for Disease Control estimated arthritis-related medical costs are $15 billion annually. Currently available therapies are often ineffective in controlling autoimmune inflammatory arthritis like rheumatoid arthritis and psoriatic arthritis. Understanding the mechanisms that cause and regulate arthritis is critical for the development of new, better and more specific therapies. Both rheumatoid arthritis and psoriatic arthritis synovial tissues have a highly invasive behavior that leads to cartilage and bone destruction. The purpose of the synovial tissue collection program is to obtain human synovial tissue samples from patients with rheumatoid arthritis, psoriatic arthritis and controls (normals undergoing trauma related surgery, or osteoarthritis). These tissues are essential for the identification of differentially expressed genes that may account for the disease-associated invasive and destructive behavior. Additionally, primary synovial cell lines will be generated from these tissues, and used to validate the gene expression findings from tissues, and well as in in vitro functional studies. It is anticipated that these studies will identify novel therapeutic targets. Assays that will be performed using this material include biochemical assays to determine the activation and invasive status, and microarray experiments. Quantitative reverse transcriptase polymerase chain reaction and immunohistochemistry will be used to validate the microarray findings.